animal tissues and organ systems chapter 20. stem cells undifferentiated cells with potential to...
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Animal Tissues and Organ Systems
Chapter 20
Stem Cells
• Undifferentiated cells with potential to develop into many cell types– Embryonic stem cells, more
versatile– Adult stem cells, less
versatile
Body Organization
• Tissue– Group of cells performing same task
• Organ– Two or more tissues performing same task
• Organ system– Two or more organs performing same task
Tissues
• Groups of cells and intercellular substances
that interact in one or more tasks
• Example: muscle tissue
Organs
• Group of tissues organized to perform a task or tasks
• Example: Heart is an organ that pumps blood through body
• Heart consists of muscle tissue, nervous tissue, connective tissue, and epithelial tissue
Organ Systems
• Groups of organs that interact physically and/or chemically to perform a common task
• Example: Circulatory system includes heart, arteries, and other vessels that transport blood through the body
Homeostasis
• Stable operating conditions in the internal environment
• Brought about by coordinated activities of cells, tissues, organs, and organ systems
4 Types of Tissues
• Epithelial tissues
• Connective tissues
• Muscle tissues
• Nervous tissues
Epithelial Tissues
• Line body surfaces, cavities, ducts, and
tubes
• One free surface faces a body fluid or the
environmentsimplesquamousepithelium
basementmembrane
connective tissue
simple epithelium
basement membrane
connective tissue
free surface of epithelium
Epithelium
Glands
• Secretory organs derived from epithelium
• Exocrine glands have ducts or tubes• Endocrine glands are ductless
Cell Junctions• Tight junctions
prevent leaks • Gap junctions
connect abutting cytoplasms
• Adhering junctions cement cells together
Tight junctions
Adhering junction
Gap junctions
Connective Tissues
• Most abundant tissues in the body• Fibroblasts secrete – polysaccharide “ground substance” that
surrounds and supports cells– fibers of collagen and/or elastin
Soft Connective Tissues• Loose connective tissue• Dense, irregular connective tissue• Dense, regular connective tissue
Specialized Connective Tissues• Cartilage• Bone tissue• Adipose tissue• Blood
red blood cell
white blood cell
platelet
Fig. 20-3g, p.342
cells and platelets of blood
Muscle Tissue
• Cells contract when stimulated• Moves body and specific body parts• 3 types– Skeletal– Cardiac– Smooth
Skeletal Muscle
• Attaches to and moves bones
• Long, cylindrical cells• Striated cells • Voluntary control
nucleus
Smooth Muscle• Located in soft internal
organs and blood vessels • Cells taper at ends• Cells not striated• Not under voluntary control
where abutting cells meet
Cardiac Muscle
• Present only in heart• Cells are branching– ends of cells joined by communication
junctions
• Cells striated• Not under voluntary control
cell nucleus
Nervous Tissue• Detects stimuli, integrates information,
and relays commands for response• Consists of excitable neurons and
supporting neuroglial cells
Functional zones of a motor neuron
Neurons
Neurons
• Excitable cells• Stimulus sends electrical impulse along
plasma membrane• Transmits information to other neurons,
muscles or glands
Neuroglia
• Neuroglial cells make up more than half of nervous tissue
• Protect and support neurons
11 Major Organ Systems• Integumentary • Nervous• Muscular• Skeletal• Circulatory• Endocrine• Lymphatic
• Respiratory
• Digestive
• Urinary
• Reproductive
Nervous System
Muscular System Skeletal System
Circulatory System
Endocrine System
Fig. 20-6, p.344a1
Integumentary System
11 Major Organ Systems
Lymphatic System
Respiratory System
Digestive System
Urinary System
Reproductive System
Fig. 20-6a2, p.344
11 Major Organ Systems
midsagittal plane
transverse planefrontal plane
dorsal surface
ventral surface
anteriorposterior
Fig. 20-6b, p.345
Position References:Animals
Position References: Humans
frontal plane(aqua)
transverse plane(yellow)
midsagittal plane (green)
Major Body Cavities
• Cranial cavity
• Spinal cavity
• Thoracic cavity
• Abdominal cavity
• Pelvic cavity
cranial cavity
spinal cavity
thoracic cavity
abdominal cavity
pelvic cavity
Fig. 20-6d, p.345
Primary Tissues
• Three primary tissues in vertebrate embryos give rise to all adult tissues:
EctodermMesodermEndoderm
Skin: An Organ System
• Epidermis: Stratified epithelium
• Dermis: Dense connective tissues
• Hypodermis: Loose connective tissue and adipose tissue
hair
epidermis
dermis
hypodermis(below skin, not part of it)
oil gland
hair follicle
blood vessels
smooth muscle
sweat gland
sensoryneuron
Fig. 20-7a, p.346
outermostepidermallayer (alldead cells)
keratinizedcells beingflattened
rapidlydividingcells ofepidermis
dermis
Fig. 20-7b, p.346
Functions of Human Skin
• Protects body from injury, dehydration, UV radiation, and some pathogens
• Helps control temperature• Receives external stimuli• Involved in vitamin D production
Sun Damages Skin• UV light stimulates melanin production– tans skin
• Tan protects inner layers against UV damage
• UV exposure causes– elastin fibers to clump– skin to age prematurely– skin cancer
Langerhans Cells
• White blood cells in skin• Attack viruses and bacteria• Stimulate immune system• Are damaged by UV exposure
Epithelial Tissues
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